/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using System.Text;
using System.IO;
using PdfSharp.Internal;
using PdfSharp.Pdf.IO;
using PdfSharp.Pdf.Internal;

namespace PdfSharp.Pdf
{
  /// <summary>
  /// Determines the encoding of a PdfString or PdfStringObject.
  /// </summary>
  [Flags]
  public enum PdfStringEncoding
  {
    /// <summary>
    /// The characters of the string are actually bytes with an unknown or context specific meaning or encoding.
    /// With this encoding the 8 high bits of each character is zero.
    /// </summary>
    RawEncoding       = 0x00,

    /// <summary>
    /// Not yet used by PDFsharp.
    /// </summary>
    StandardEncoding = 0x01,

    /// <summary>
    /// The characters of the string are actually bytes with PDF document encoding.
    /// With this encoding the 8 high bits of each character is zero.
    /// </summary>
    PDFDocEncoding = 0x02,

    /// <summary>
    /// The characters of the string are actually bytes with Windows ANSI encoding.
    /// With this encoding the 8 high bits of each character is zero.
    /// </summary>
    WinAnsiEncoding = 0x03,

    /// <summary>
    /// Not yet used by PDFsharp.
    /// </summary>
    MacRomanEncoding = 0x04,  // not used by PDFsharp

    /// <summary>
    /// Not yet used by PDFsharp.
    /// </summary>
    MacExpertEncoding = 0x05,  // not used by PDFsharp

    /// <summary>
    /// The characters of the string are Unicode characters.
    /// </summary>
    Unicode = 0x06,
  }

  /// <summary>
  /// Internal wrapper for PdfStringEncoding.
  /// </summary>
  [Flags]
  enum PdfStringFlags
  {
    RawEncoding       = 0x00,
    StandardEncoding  = 0x01,  // not used by PDFsharp
    PDFDocEncoding    = 0x02,
    WinAnsiEncoding   = 0x03,
    MacRomanEncoding  = 0x04,  // not used by PDFsharp
    MacExpertEncoding = 0x05,  // not used by PDFsharp
    Unicode           = 0x06,
    EncodingMask      = 0x0F,

    HexLiteral        = 0x80,
  }

  /// <summary>
  /// Represents a direct text string value.
  /// </summary>
  [DebuggerDisplay("({Value})")]
  public sealed class PdfString : PdfItem
  {
    /// <summary>
    /// Initializes a new instance of the <see cref="PdfString"/> class.
    /// </summary>
    public PdfString()
    {
      this.flags = PdfStringFlags.RawEncoding;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfString"/> class.
    /// </summary>
    /// <param name="value">The value.</param>
    public PdfString(string value)
    {
      this.value = value;
      this.flags = PdfStringFlags.RawEncoding;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfString"/> class.
    /// </summary>
    /// <param name="value">The value.</param>
    /// <param name="encoding">The encoding.</param>
    public PdfString(string value, PdfStringEncoding encoding)
    {
      this.value = value;
      //if ((flags & PdfStringFlags.EncodingMask) == 0)
      //  flags |= PdfStringFlags.PDFDocEncoding;
      this.flags = (PdfStringFlags)encoding;
    }

    internal PdfString(string value, PdfStringFlags flags)
    {
      this.value = value;
      //if ((flags & PdfStringFlags.EncodingMask) == 0)
      //  flags |= PdfStringFlags.PDFDocEncoding;
      this.flags = flags;
    }

    /// <summary>
    /// Gets the number of characters in this string.
    /// </summary>
    public int Length
    {
      get { return this.value == null ? 0 : this.value.Length; }
    }

    /// <summary>
    /// Gets the encoding.
    /// </summary>
    public PdfStringEncoding Encoding
    {
      get { return (PdfStringEncoding)(this.flags & PdfStringFlags.EncodingMask); }
      //set { this.flags = (this.flags & ~PdfStringFlags.EncodingMask) | ((PdfStringFlags)value & PdfStringFlags.EncodingMask);}
    }

    /// <summary>
    /// Gets a value indicating whether the string is a hexadecimal literal.
    /// </summary>
    public bool HexLiteral
    {
      get { return (this.flags & PdfStringFlags.HexLiteral) != 0; }
      //set { this.flags = value ? this.flags | PdfStringFlags.HexLiteral : this.flags & ~PdfStringFlags.HexLiteral;}
    }

    internal PdfStringFlags Flags
    {
      get { return this.flags; }
      //set { this.flags = value; }
    }
    PdfStringFlags flags;

    /// <summary>
    /// Gets the string value.
    /// </summary>
    public string Value
    {
      // This class must behave like a value type. Therefore it cannot be changed (like System.String).
      get { return this.value == null ? "" : this.value; }
    }
    string value;

    /// <summary>
    /// Gets or sets the string value for encryption purposes.
    /// </summary>
    internal byte[] EncryptionValue
    {
      // TODO: Unicode case is not handled!
      get {return this.value == null ? new byte[0] : PdfEncoders.RawEncoding.GetBytes(this.value);}
      // BUG: May lead to trouble with the value semantics of PdfString
      set {this.value = PdfEncoders.RawEncoding.GetString(value);}
    }

    /// <summary>
    /// Returns the string.
    /// </summary>
    public override string ToString()
    {
      return this.value;
    }

    /// <summary>
    /// Writes the string DocEncoded.
    /// </summary>
    internal override void WriteObject(PdfWriter writer)
    {
      writer.Write(this);
    }
  }
}
